The 2015 United SportsCar Championship (known for sponsorship reasons as the 2015 Tudor United SportsCar Championship) was the second season of the International Motor Sports Association's United SportsCar Championship and the last to be held under that name. It was also the 45th overall season of the IMSA GT championship tracing its lineage to the 1971 IMSA season. It began on January 24 with the 24 Hours of Daytona.[1] and ended on October 3 at Petit Le Mans.